So the motor noise happens when you are not using the jacks and when they are up? If that is the case, I think there are two possibilities.
Either you have a slow hydraulic leak and the pressure is dropping or your pressure sensor is failing.
When the pressure drops due to a leak or the pressure sensor is failing and thinks the pressure is too low when it isn't, there appears not to be enough pressure to keep the jacks retracted. If you have the parking brake off and the engine is running, the system will attempt to run the motor to retract the jacks as a safety measure before you would try to drive away.
I had a case where my pressure sensor failed so when the engine was running and I released the parking brake, the leveler motor fired up even though the jacks were retracted because the sytem thought the pressure was too low. The motor would run until it tripped the 100A breaker and then I would get a Low Voltage Alarm.
Once I replaced the pressure sensor (got one off Amazon), it solved the problem. You may want to look for possible oil spots and signs of a leak. if you don't find anything, it could be the sensor.